Bivariate Spatial Pattern between Smoking Prevalence and Lung Cancer Screening in US Counties

Area of Science:

• Public Health
• Radiology
• Health Services Research

Background:

• Lung cancer screening (LCS) using low-dose computed tomography (LDCT) has been a Medicare-covered preventive service since 2015.
• Geographic disparities in LDCT provider access may limit LCS uptake among eligible populations.
• Understanding spatial access to LDCT is crucial for addressing screening inequities.

Purpose of the Study:

• To evaluate the availability of LDCT services for older adults in the US.
• To explore the ecological correlation between LDCT service availability and smoking prevalence.
• To identify geographic disparities in LCS access.

Main Methods:

• Utilized Medicare claims data (Physician and Other Supplier Public Use File) from 2016.
• Defined LDCT provider coverage areas using 30-mile Euclidean distance buffers.
• Mapped county-level LDCT provider density and smoking prevalence using bivariate choropleth maps.

Main Results:

• Nearly 20% of census tracts lacked LDCT providers within 30 miles; 46% of counties had no LDCT services.
• Median LDCT density was 0.5 providers per 1000 Medicare beneficiaries (IQR: 0-5.3).
• High LDCT availability concentrated in the Northeast, misaligned with higher smoking prevalence in central and southern US.

Conclusions:

• Significant geographic disparities exist in LDCT service availability for Medicare beneficiaries.
• Areas with high smoking prevalence often have limited access to LDCT services.
• Targeted workforce and capacity building are needed to reduce disparities in LCS access and utilization.